Add dummy .h files to Digispark_Examples and DigiXBetaBonus folders

[per1234]

In Arduino IDE 1.6.6 and 1.6.7 these are considered invalid libraries without a header file and this causes an Invalid library... warning whenever a Digispark board is selected from the Tools > Board menu or Boards Manager or Library Manager is opened with a Digispark board selected and the sketches don't appear in the File > Example menu.

Closes https://github.com/digistump/DigistumpArduino/issues/22

[FlackMonkey]

Same thing with usb digispark(default 16.5mhz) attiny85 on windows XP and Arduino IDE 1.6.7

WARNING: Category '' in library SPI is not valid. Setting to 'Uncategorized' Warning: platform.txt from core 'Digistump AVR Boards' contains deprecated recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} "{build.path}/{archive_file}" "{object_file}", automatically converted to recipe.ar.pattern="{compiler.path}{compiler.ar.cmd}" {compiler.ar.flags} "{archive_file_path}" "{object_file}". Consider upgrading this core. Warning: platform.txt from core 'Digistump AVR Boards' contains deprecated recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" {compiler.c.elf.flags} -mmcu={build.mcu} -o "{build.path}/{build.project_name}.elf" {object_files} "{build.path}/{archive_file}" "-L{build.path}" -lm, automatically converted to recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" {compiler.c.elf.flags} -mmcu={build.mcu} -o "{build.path}/{build.project_name}.elf" {object_files} "{archive_file_path}" "-L{build.path}" -lm. Consider upgrading this core.

Sketch uses 668 bytes (11%) of program storage space. Maximum is 6,012 bytes. Global variables use 9 bytes of dynamic memory. Running Digispark Uploader... Plug in device now... (will timeout in 60 seconds) Assertion failed: res >= 4, file library/micronucleus_lib.c, line 100

This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Invalid library found in C:\Documents and Settings\ADMIN\Local Settings\Application Data\Arduino15\packages\digistump\hardware\avr\1.6.5\libraries\Digispark_Examples: C:\Documents and Settings\ADMIN\Local Settings\Application Data\Arduino15\packages\digistump\hardware\avr\1.6.5\libraries\Digispark_Examples Invalid library found in C:\Documents and Settings\ADMIN\Local Settings\Application Data\Arduino15\packages\digistump\hardware\avr\1.6.5\libraries\Digispark_Examples: C:\Documents and Settings\ADMIN\Local Settings\Application Data\Arduino15\packages\digistump\hardware\avr\1.6.5\libraries\Digispark_Examples Invalid library found in C:\Documents and Settings\ADMIN\Local Settings\Application Data\Arduino15\packages\digistump\hardware\avr\1.6.5\libraries\Digispark_Examples: C:\Documents and Settings\ADMIN\Local Settings\Application Data\Arduino15\packages\digistump\hardware\avr\1.6.5\libraries\Digispark_Examples

[digistump]

Thanks @per1234 - merging for todays release